A rare and delightful novelty from Vienna's golden age of operetta publishing, this "Emel-Karten" Nr. 15 is a folded music-postcard — its front bearing a richly colored genre painting of a young man serenading beneath a moonlit bridge with guitar in hand, a vision straight from Schubert's romantic imagination, while its interior unfolds to reveal a full printed score of Ständchen ("Serenade," "Leise flehen meine Lieder") from the song cycle Schwanengesang, here attributed to the operetta Hannerl (Dreimäderlhaus, Part II) — the enormously popular Viennese pasticcio of 1916 built on Schubert's melodies. The reverse features a portrait of Franz Schubert in blue Art Nouveau decorative framing, publisher's imprint for Lyra Verlag / H. Molitor, Leipzig and Vienna, and advertising for the "Emel Karten" series of modern operetta hits. Unused and never mailed, this charming three-panel artifact bridges postcard, sheet music, and operetta ephemera in a single object — exceptionally uncommon.